path: root/src/glx/x11/dri_glx.c

/**************************************************************************

Copyright 1998-1999 Precision Insight, Inc., Cedar Park, Texas.
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/* $XFree86: xc/lib/GL/dri/dri_glx.c,v 1.14 2003/07/16 00:54:00 dawes Exp $ */

/*
 * Authors:
 *   Kevin E. Martin <kevin@precisioninsight.com>
 *   Brian Paul <brian@precisioninsight.com>
 *
 */

#ifdef GLX_DIRECT_RENDERING

#include <unistd.h>
#include <X11/Xlibint.h>
#include <X11/extensions/Xext.h>
#include <X11/extensions/extutil.h>
#include "glxclient.h"
#include "xf86dri.h"
#include "sarea.h"
#include <stdio.h>
#include <dlfcn.h>
#include "dri_glx.h"
#include <sys/types.h>
#include <stdarg.h>

#ifndef RTLD_NOW
#define RTLD_NOW 0
#endif
#ifndef RTLD_GLOBAL
#define RTLD_GLOBAL 0
#endif


#ifndef DEFAULT_DRIVER_DIR
/* this is normally defined in Mesa/configs/default with DRI_DRIVER_SEARCH_PATH */
#define DEFAULT_DRIVER_DIR "/usr/X11R6/lib/modules/dri"
#endif

static __DRIdriver *Drivers = NULL;


/*
 * printf wrappers
 */

static void InfoMessageF(const char *f, ...)
{
    va_list args;
    const char *env;

    if ((env = getenv("LIBGL_DEBUG")) && strstr(env, "verbose")) {
	fprintf(stderr, "libGL: ");
	va_start(args, f);
	vfprintf(stderr, f, args);
	va_end(args);
    }
}

static void ErrorMessageF(const char *f, ...)
{
    va_list args;

    if (getenv("LIBGL_DEBUG")) {
	fprintf(stderr, "libGL error: ");
	va_start(args, f);
	vfprintf(stderr, f, args);
	va_end(args);
    }
}


/**
 * Extract the ith directory path out of a colon-separated list of paths.  No
 * more than \c dirLen characters, including the terminating \c NUL, will be
 * written to \c dir.
 *
 * \param index  Index of path to extract (starting at zero)
 * \param paths  The colon-separated list of paths
 * \param dirLen Maximum length of result to store in \c dir
 * \param dir    Buffer to hold the extracted directory path
 *
 * \returns
 * The number of characters that would have been written to \c dir had there
 * been enough room.  This does not include the terminating \c NUL.  When
 * extraction fails, zero will be returned.
 * 
 * \todo
 * It seems like this function could be rewritten to use \c strchr.
 */
static size_t
ExtractDir(int index, const char *paths, int dirLen, char *dir)
{
   int i, len;
   const char *start, *end;

   /* find ith colon */
   start = paths;
   i = 0;
   while (i < index) {
      if (*start == ':') {
         i++;
         start++;
      }
      else if (*start == 0) {
         /* end of string and couldn't find ith colon */
         dir[0] = 0;
         return 0;
      }
      else {
         start++;
      }
   }

   while (*start == ':')
      start++;

   /* find next colon, or end of string */
   end = start + 1;
   while (*end != ':' && *end != 0) {
      end++;
   }

   /* copy string between <start> and <end> into result string */
   len = end - start;
   if (len > dirLen - 1)
      len = dirLen - 1;
   strncpy(dir, start, len);
   dir[len] = 0;

   return( end - start );
}


/**
 * Versioned name of the expected \c __driCreateNewScreen function.
 * 
 * The version of the last incompatible loader/driver inteface change is
 * appended to the name of the \c __driCreateNewScreen function.  This
 * prevents loaders from trying to load drivers that are too old.
 * 
 * \todo
 * Create a macro or something so that this is automatically updated.
 */
static const char createNewScreenName[] = "__driCreateNewScreen_20070105";


/**
 * Try to \c dlopen the named driver.
 *
 * This function adds the "_dri.so" suffix to the driver name and searches the
 * directories specified by the \c LIBGL_DRIVERS_PATH environment variable in
 * order to find the driver.
 *
 * \param driverName - a name like "tdfx", "i810", "mga", etc.
 *
 * \returns
 * A handle from \c dlopen, or \c NULL if driver file not found.
 */
static __DRIdriver *OpenDriver(const char *driverName)
{
   void *glhandle = NULL;
   char *libPaths = NULL;
   char libDir[1000];
   int i;
   __DRIdriver *driver;

   /* First, search Drivers list to see if we've already opened this driver */
   for (driver = Drivers; driver; driver = driver->next) {
      if (strcmp(driver->name, driverName) == 0) {
         /* found it */
         return driver;
      }
   }

   /* Attempt to make sure libGL symbols will be visible to the driver */
   glhandle = dlopen("libGL.so.1", RTLD_NOW | RTLD_GLOBAL);

   if (geteuid() == getuid()) {
      /* don't allow setuid apps to use LIBGL_DRIVERS_PATH */
      libPaths = getenv("LIBGL_DRIVERS_PATH");
      if (!libPaths)
         libPaths = getenv("LIBGL_DRIVERS_DIR"); /* deprecated */
   }
   if (!libPaths)
      libPaths = DEFAULT_DRIVER_DIR;

   for ( i = 0 ; ExtractDir(i, libPaths, 1000, libDir) != 0 ; i++ ) {
      char realDriverName[200];
      void *handle = NULL;

      
      /* If TLS support is enabled, try to open the TLS version of the driver
       * binary first.  If that fails, try the non-TLS version.
       */
#ifdef GLX_USE_TLS
      snprintf(realDriverName, 200, "%s/tls/%s_dri.so", libDir, driverName);
      InfoMessageF("OpenDriver: trying %s\n", realDriverName);
      handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL);
#endif

      if ( handle == NULL ) {
	 snprintf(realDriverName, 200, "%s/%s_dri.so", libDir, driverName);
	 InfoMessageF("OpenDriver: trying %s\n", realDriverName);
	 handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL);
      }

      if ( handle != NULL ) {
         /* allocate __DRIdriver struct */
         driver = (__DRIdriver *) Xmalloc(sizeof(__DRIdriver));
         if (!driver)
            break; /* out of memory! */
         /* init the struct */
         driver->name = __glXstrdup(driverName);
         if (!driver->name) {
            Xfree(driver);
            driver = NULL;
            break; /* out of memory! */
         }

         driver->createNewScreenFunc = (PFNCREATENEWSCREENFUNC)
            dlsym(handle, createNewScreenName);

         if ( driver->createNewScreenFunc == NULL ) {
            /* If the driver doesn't have this symbol then something's
             * really, really wrong.
             */
            ErrorMessageF("%s not defined in %s_dri.so!\n"
			  "Your driver may be too old for this libGL.\n",
			  createNewScreenName, driverName);
            Xfree(driver);
            driver = NULL;
            dlclose(handle);
            continue;
         }
         driver->handle = handle;
         /* put at head of linked list */
         driver->next = Drivers;
         Drivers = driver;
         break;
      }
      else {
	 ErrorMessageF("dlopen %s failed (%s)\n", realDriverName, dlerror());
      }
   }

   if (!driver)
      ErrorMessageF("unable to load driver: %s_dri.so\n", driverName);

   if (glhandle)
      dlclose(glhandle);

   return driver;
}


/*
 * Given a display pointer and screen number, determine the name of
 * the DRI driver for the screen. (I.e. "r128", "tdfx", etc).
 * Return True for success, False for failure.
 */
static Bool GetDriverName(Display *dpy, int scrNum, char **driverName)
{
   int directCapable;
   Bool b;
   int driverMajor, driverMinor, driverPatch;

   *driverName = NULL;

   if (!XF86DRIQueryDirectRenderingCapable(dpy, scrNum, &directCapable)) {
      ErrorMessageF("XF86DRIQueryDirectRenderingCapable failed\n");
      return False;
   }
   if (!directCapable) {
      ErrorMessageF("XF86DRIQueryDirectRenderingCapable returned false\n");
      return False;
   }

   b = XF86DRIGetClientDriverName(dpy, scrNum, &driverMajor, &driverMinor,
                                  &driverPatch, driverName);
   if (!b) {
      ErrorMessageF("Cannot determine driver name for screen %d\n", scrNum);
      return False;
   }

   InfoMessageF("XF86DRIGetClientDriverName: %d.%d.%d %s (screen %d)\n",
	     driverMajor, driverMinor, driverPatch, *driverName, scrNum);

   return True;
}


/*
 * Given a display pointer and screen number, return a __DRIdriver handle.
 * Return NULL if anything goes wrong.
 */
__DRIdriver *driGetDriver(Display *dpy, int scrNum)
{
   char *driverName;
   if (GetDriverName(dpy, scrNum, &driverName)) {
      __DRIdriver *ret;
      ret = OpenDriver(driverName);
      if (driverName)
     	 Xfree(driverName);
      return ret;
   }
   return NULL;
}


/*
 * Exported function for querying the DRI driver for a given screen.
 *
 * The returned char pointer points to a static array that will be
 * overwritten by subsequent calls.
 */
const char *glXGetScreenDriver (Display *dpy, int scrNum) {
   static char ret[32];
   char *driverName;
   if (GetDriverName(dpy, scrNum, &driverName)) {
      int len;
      if (!driverName)
	 return NULL;
      len = strlen (driverName);
      if (len >= 31)
	 return NULL;
      memcpy (ret, driverName, len+1);
      Xfree(driverName);
      return ret;
   }
   return NULL;
}


/*
 * Exported function for obtaining a driver's option list (UTF-8 encoded XML).
 *
 * The returned char pointer points directly into the driver. Therefore
 * it should be treated as a constant.
 *
 * If the driver was not found or does not support configuration NULL is
 * returned.
 *
 * Note: The driver remains opened after this function returns.
 */
const char *glXGetDriverConfig (const char *driverName) {
   __DRIdriver *driver = OpenDriver (driverName);
   if (driver)
      return dlsym (driver->handle, "__driConfigOptions");
   else
      return NULL;
}


/* This function isn't currently used.
 */
static void driDestroyDisplay(Display *dpy, void *private)
{
    __DRIdisplayPrivate *pdpyp = (__DRIdisplayPrivate *)private;

    if (pdpyp) {
        const int numScreens = ScreenCount(dpy);
        int i;
        for (i = 0; i < numScreens; i++) {
            if (pdpyp->libraryHandles[i])
                dlclose(pdpyp->libraryHandles[i]);
        }
        Xfree(pdpyp->libraryHandles);
	Xfree(pdpyp);
    }
}


/*
 * Allocate, initialize and return a __DRIdisplayPrivate object.
 * This is called from __glXInitialize() when we are given a new
 * display pointer.
 */
void *driCreateDisplay(Display *dpy, __DRIdisplay *pdisp)
{
    const int numScreens = ScreenCount(dpy);
    __DRIdisplayPrivate *pdpyp;
    int eventBase, errorBase;
    int major, minor, patch;
    int scrn;

    /* Initialize these fields to NULL in case we fail.
     * If we don't do this we may later get segfaults trying to free random
     * addresses when the display is closed.
     */
    pdisp->private = NULL;
    pdisp->destroyDisplay = NULL;

    if (!XF86DRIQueryExtension(dpy, &eventBase, &errorBase)) {
	return NULL;
    }

    if (!XF86DRIQueryVersion(dpy, &major, &minor, &patch)) {
	return NULL;
    }

    pdpyp = (__DRIdisplayPrivate *)Xmalloc(sizeof(__DRIdisplayPrivate));
    if (!pdpyp) {
	return NULL;
    }

    pdpyp->driMajor = major;
    pdpyp->driMinor = minor;
    pdpyp->driPatch = patch;

    pdisp->destroyDisplay = driDestroyDisplay;

    /* allocate array of pointers to createNewScreen funcs */
    pdisp->createNewScreen = (PFNCREATENEWSCREENFUNC *)
      Xmalloc(numScreens * sizeof(void *));
    if (!pdisp->createNewScreen) {
       Xfree(pdpyp);
       return NULL;
    }

    /* allocate array of library handles */
    pdpyp->libraryHandles = (void **) Xmalloc(numScreens * sizeof(void*));
    if (!pdpyp->libraryHandles) {
       Xfree(pdisp->createNewScreen);
       Xfree(pdpyp);
       return NULL;
    }

    /* dynamically discover DRI drivers for all screens, saving each
     * driver's "__driCreateScreen" function pointer.  That's the bootstrap
     * entrypoint for all DRI drivers.
     */
    for (scrn = 0; scrn < numScreens; scrn++) {
        __DRIdriver *driver = driGetDriver(dpy, scrn);
        if (driver) {
           pdisp->createNewScreen[scrn] = driver->createNewScreenFunc;
           pdpyp->libraryHandles[scrn] = driver->handle;
        }
        else {
           pdisp->createNewScreen[scrn] = NULL;
           pdpyp->libraryHandles[scrn] = NULL;
        }
    }

    return (void *)pdpyp;
}

#endif /* GLX_DIRECT_RENDERING */